Methyl aminolevulinate (MAL) photodynamic therapy (PDT), an established nonsurgical intervention for nodular basal cell carcinoma (nBCC), does not induce changes that increase the aggressiveness of tumors in patients recurrent nBCC, study data published in Dermatologic Therapy suggests.

Researchers from Spain conducted a retrospective analysis of nBCCs treated with MAL-PDT at the Department of Dermatology at the San Jorge Hospital from 2006 to 2015. The investigators only analyzed patients with histologically confirmed primary and recurring tumors. In total, 15 nBCCs resistant to 2 sessions of MAL-PDT were included in the final analysis.

The majority of nBCCs in this study (73.3%) were persistent BCCs, meaning they were not cured within 3 months of treatment. Approximately 26.7% of BCCs recurred during the first 2-year follow-up period. The mean tumor thickness at baseline was 2.15±1.003 mm vs 1.88±0.758 mm following treatment (P =.432).


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In subsequent biopsies of the persistent nBCCs, 81.8% retained their same histological type, and 18.2% had another histological variant, including micronodular and metatypical. A persistent nodular subtype was shown in biopsy of the 4 recurring nBCCs.

The use of MAL-PDT did not induce changes in p53 (P =.906), survivin (P =.62), or β-catenin expression (P =.625), but there was a trend towards increased EGFR immunostaining (P =1). There was also a trend towards a dense stroma without ulceration in post-PDT recurrent nBCCs (P =1).

Limitations of this study included its retrospective nature, small sample size, and the inclusion of patients from a single center.

Based on their findings, the investigators of this study suggest “it seems likely that the detection of more aggressive histological patterns in persistent nBCCs after treatment is a consequence of misclassification before treatment.”

Reference

Gracia-Cazaña T, Nicolás J, Cerro-Muñoz PA, González S, Juarranz Á, Gilaberte Y. Comparative histological and immunohistochemical changes in recurrent nodular basal cell carcinoma after photodynamic therapy. Published online January 13, 2021. Dermatol Ther. doi:10.1111/dth.14779